In 2009, she was nominated to the position by President Barack Obama.[2] Ortiz is both the first woman and the first Hispanic to serve as U.S. Attorney for Massachusetts. She succeeded Michael Sullivan in that position, with Michael J. Loucks serving as the interim U.S. Attorney between Sullivan's resignation and Ortiz's confirmation.[3] Noteworthy prosecutions by her office include those of Whitey Bulger, Tarek Mehanna, Aaron Swartz, and Dzhokhar Tsarnaev.

In May 2009, Senators Ted Kennedy and John Kerry recommended Ortiz to President Obama for the vacant United States Attorney position in the District of Massachusetts.[8] On September 18, Obama nominated Ortiz for the position.[2] On November 5, the United States Senate confirmed her appointment by unanimous consent.[8]

Ortiz is both the first woman and the first Hispanic to serve as United States Attorney for the District of Massachusetts.[9][10]

In 2011, Ortiz's office was responsible for the prosecution of GlaxoSmithKline general counsel Lauren Stevens. Ultimately, the court dismissed the case, ruling that "it would be a miscarriage of justice to permit this case to go to the jury."[11][12]

Carmen Ortiz's office led the prosecution of mobster Whitey Bulger. On July 6, 2011, Bulger was arraigned in federal court. He pleaded not guilty to 48 charges, including 19 counts of murder, extortion, money laundering, obstruction of justice, perjury, narcotics distribution and weapons violations.[13]

Ortiz's office also led the prosecution of Bulger's girlfriend Catherine Greig. In March 2012, Greig plead guilty to conspiracy to harbor a fugitive, identity fraud, and conspiracy to commit identity fraud. On June 12, 2012, she was sentenced to eight years' confinement in a federal penitentiary.[14]

On March 23, 2012, Ortiz's office secured grand jury indictments against former state Probation Commissioner John J. O’Brien and two of his former deputies, Elizabeth Tavares and William Burke III, for their involvement in running a sham hiring system in which friends and family members of legislators and politically connected job seekers were hired over more qualified applicants. Each faces one count of racketeering conspiracy and 10 counts of mail fraud for sending rejection letters to applicants they knew they were never going to consider. If convicted, they face up to 20 years in prison on each of the 11 counts. Ortiz said the indictments are “one step in an ongoing investigation.”[15][16]

Carmen Ortiz led the prosecution of American pharmacist Tarek Mehanna, who was accused of, among other crimes, translating and posting online materials described by prosecutors as Al Qaedapropaganda.[17] Mehanna's lawyers argued that he never tried to join an armed group and never tried to hurt anyone, and that his internet activities were protected under the U.S. First Amendment.[18] In April 2012, Mehanna was sentenced in federal court in Boston on four terrorism-related charges and three others related to lying to agents of the FBI and other U.S. federal officials.

Ortiz came under fire after her office was involved in the January 19, 2013 arrest of a man who reportedly "looks very much like" a wanted drug suspect.[19] The man was released by a federal magistrate the following day after prosecutors admitted "significant doubt" that the arrested man was indeed the suspect.[20] Ortiz shall also pursue the recent $1.1 Million 'Insider Trading' scam involving two Indian Americans Iftikar Ahmed & Amit Kanodia which involved sharing of insider information leading to illegal gains in the NYSE. [21]

Ortiz was "admonished by a federal appeals court in 2004 for advocating a harsher jail term for a fraud defendant than she had promised him in a plea-bargain agreement."[22] In a plea deal, Ortiz had agreed to leniency, but she "substantively argued" for a harsher sentence.[22] The Appeals Court ruled that Ortiz "violated the plea agreement it entered into with Gonczy," and it vacated the sentence.[23]

Ortiz's office sought to confiscate the Motel Caswell in Tewksbury, Massachusetts from its owner, Russ Caswell. Prosecutors contended that, despite the fact that Caswell himself had never been charged with any crime, his property was subject to civil forfeiture as a long-term site of criminal activity. Ortiz's spokeswoman said "The government believed that this was an important case, not only for the town of Tewksbury, which has been plagued for decades by the criminal activity at Motel Caswell, but because of the important deterrent message it sends to others who may turn a blind eye to crime occurring at their place of business." The property had been the location of 15 drug crimes between 1994 and 2008, which Caswell said is small considering that he rents about 14,000 rooms per year.[24][25][26][27] Caswell was represented by the Institute for Justice, a non-profit libertarian public interest law firm that frequently intervenes in asset forfeiture cases.[28] On January 24, 2013, U.S. Magistrate Judge Judith Dein sided with Caswell.[29][30] In a written decision, Dein dismissed the government’s forfeiture action, ruling that Caswell, "who was trying to eke out an income from a business located in a drug-infested area that posed great risks to the safety of him and his family, took all reasonable steps to prevent crime. The Government’s resolution of the crime problem should not be to simply take his Property."[31] In the ruling, the court criticized the prosecution for "stretching the evidence" and engaging in "gross exaggeration."[32][33]

After considering an appeal,[34] her office announced that in March 2013 that they would not pursue the matter further.[35]

Ortiz's office prosecuted computer programmer and Internet activist Aaron Swartz. In 2011, Swartz was arrested for unauthorized, bulk downloading of free articles from internet archive JSTOR, in violation of the JSTOR's terms of use.[36][37][38] In a 2011 press release announcing Swartz's indictment on federal charges, Ortiz said "stealing is stealing whether you use a computer command or a crowbar, and whether you take documents, data or dollars." [39] After State Prosecutors dropped their charges, federal prosecutors filed a superseding indictment adding nine more felony counts, which increased Swartz's maximum criminal exposure to 50 years of imprisonment and $1 million in fines.

The prosecution brought by Ortiz involved what was characterized by numerous critics such as former White House Counsel John Dean as "overcharging" and "overzealous" prosecution for the alleged computer crimes.[40][41]

In all, prosecutors charged Swartz with 13 felony counts, despite the fact that both MIT and JSTOR had chosen not to pursue civil litigation; he faced 30 years' imprisonment.[42]Swartz committed suicide on January 11, 2013,[43][44] before the case came to trial. More than 60,000 people petitioned the White House to remove Ortiz from office for "overreach."[45][46][47][48] On January 15, 2013, following his suicide, all charges against Swartz were dropped.[43][44] The next day, Ortiz issued a statement saying that her office had never intended to seek maximum penalties against Aaron Swartz.[49]

Massachusetts Lawyers Weekly published an op-ed piece by Massachusetts criminal defense attorney Harvey Silverglate about the case. He said attorneys familiar with the case had told him the Middlesex County District Attorney's office had planned for Swartz's case to be "continued without a finding, with Swartz duly admonished and then returned to civil society to continue his pioneering electronic work in a less legally questionable manner."[50][51] "Under such a disposition," Silverglate later told CNET's Declan McCullagh, "the charge is held in abeyance ("continued") without any verdict ("without a finding"). The defendant is on probation for a period of a few months up to maybe a couple of years at the most; if the defendant does not get into further legal trouble, the charge is dismissed, and the defendant has no criminal record. This is what the lawyers expected to happen when Swartz was arrested. But then the feds took over...."[51] "Tragedy intervened," Silverglate wrote, "when Ortiz's office took over the case to send 'a message.'"[50]

Boston's WBUR reported that Ortiz was expected to testify before the House Committee on Oversight and Government Reform's probe into the handling of the Aaron Swartz case.[40] The Department of Justice gave a private briefing about the case to the House Committee, and subsequently, in March 2013, Attorney General Eric Holder defended Ortiz's aggressive prosecution before the Senate Judiciary Committee, terming it, "a good use of prosecutorial discretion."[52]

In January, 2015, two years after Swartz’s death, the White House declined to act on the petition to remove Ortiz from office.[53]

On August 8, 2013, two of Tsarnaev's friends were indicted on federal obstruction of justice charges.[57] Another Ortiz prosecution, this time of Tamerlan's friend Khairullozhon Matanov who pleaded guilty rather than face 20 years in prison, has been described as overzealous.[58] Ortiz declared “there was nothing about this crime that was Islam associated” regarding the Boston Marathon bombing at a press conference on Wednesday. “And, we believe that, at the end of the day, the punishment that was rendered by the jury appropriately fitted the crime, a crime of terrorism, a crime that was not religiously motivated, and a crime that was intended to coerce and intimidate our country, but the response has been otherwise.” She also responded to a question about Tsarnaev’s references to Allah, Mohammed, and the Koran, with “That is that a skewed view of the religion of Islam. That is not what Islam is all about, and so when individuals utilize that, it is a radicalized view, that ideology. It’s a radical ideology, which really isn’t at the heart of what is truly a peaceful and loving religion.”[59]

Ortiz is prosecuting Gottesfeld under the Computer Fraud and Abuse Act for taking the Boston Children's Hospital website down during an online donation drive to protest the hospital's treatment of Justina Pelletier.[60][61][62] Pelletier, who was taken from her family by the hospital under a controversial Massachusetts law, ended up losing the use of her legs under the hospital's treatment plan.[63][64][65]

Ortiz has two daughters and is married to IBM executive Thomas J. Dolan; her first husband, Michael Vittorio Morisi, died in 2000.[68]

Ortiz reportedly considered a campaign for Governor of Massachusetts, but she denied interest in such a run.[69] This decision also came on the heels of the unpopular Swartz prosecution, with other critics describing Ortiz's professional record as marked by a "hands-off leadership style" and "overzealousness".[70]

^US Attorney's Office District of Massachusetts (July 19, 2011). "Alleged Hacker Charged With Stealing Over Four Million Documents from MIT Network". Press release. Archived from the original on May 26, 2012. Retrieved January 17, 2013. United States Attorney Carmen M. Ortiz said, 'Stealing is stealing whether you use a computer command or a crowbar, and whether you take documents, data or dollars. It is equally harmful to the victim whether you sell what you have stolen or give it away.'